DE3326871A1 - Process for producing synthesis gas, and burner for carrying out the process - Google Patents

Abstract

The invention relates to a process for producing synthesis gas by partial oxidation of particles containing carbon suspended in water at high temperatures and elevated pressure. By means of a centrosymmetrical arrangement of a baffle body into the path of the material streams, these are widened in accordance with the shape of the baffle body. This has the result that the combustion proceeds in an advantageous manner.

Description

Method of making theseas and burner

for carrying out the method The invention relates to a method for the production of gas mixtures containing lI2 and CO from aqueous suspensions carbonaceous solids and burners to carry out the process.

In the autothermal gasification of solid carbonaceous fuels, like the different types of coal, the required high gasification temperatures are required achieved in that part of the fuel to be gasified with free oxygen is burned. This partial oxidation takes place according to the present gasification process unpressurized or under increased pressure, in a fixed bed, in a fluidized bed or in an entrained flow.

According to a known process, the solid fuel, e.g. coal, in finely ground form mashed with water to form a suspension and in this iorm is injected into a pressure reactor via a burner. The fuel flows through during the gasification reaction the pressure reactor in cocurrent with the generated Gas in the vertical direction from the top to below. The pressure coat the reactor is lined with refractory material to protect it from overheating.

To avoid high heat losses, an uncooled one is normally used refractory lining selected.

Because of the high thermal, chemical and mechanical stress the service life of this lining is limited. It depends to a decisive extent on the temperature control in the reaction zone.

The entry of the ground fuel into the pressure reactor as a suspension can be done relatively easily with appropriate high-pressure suspension pumps.

On the other hand, the disadvantage is that the suspension is considerably less is diligent than is the case, for example, with comparable processes involving the introduction of dry dust the ball is.

After the suspension has been introduced into the reaction chamber, it must be increased the water fractions of the suspension evaporate and then the fuel particles be heated up to the degassing or gasification temperature. This process is very energy-consuming and stressed - depending on the atomization of the fuel jet through the burner - a more or less large proportion of the time during the the converting fuel particles stay in the pressure reactor. In the practical This has a very negative effect on operation and leads to unsatisfactory implementation of carbon.

With the previously known suspension burners used in compressed coal gasification can the did not describe disadvantages or only inadequately avoid. This can be remedied by increasing the reaction space. the However, improved implementation comes with great expense and high heat losses he buys. It is also possible to increase the carbon turnover by increasing the supply of oxygen to increase. You then have to have extremely high friction temperatures with a faster destruction of the refractory lining and an increased 002 concentration accept in the product gas. The selection of suitable suspension burners that Being able to mitigate or even compensate disadvantage is therefore of great practical importance to.

A known method is used to gasify coal Pressurize a suspension burner containing a premix zone. In the premix zone the oxygen supplied in a central tube and that in a coaxially arranged one Tube introduced suspension combined to form a multiphase flow. This occurs from a nozzle armored against wear and tear into the reaction room at high speed the end. Since the pressure in the mixing chamber is greater than in the reactor space, the mixture is from suspension and oxygen after leaving the burner nozzle, the compact one relaxes The beam tears apart, thereby increasing its surface area. Burner this Art lead hi smaller throughputs to a satisfactory carbon conversion. For Larger fuel throughputs, however, are sufficient to dissolve the jet through relaxation no longer. Because of the shortened residence time of the particles in the reactor as a result the high axial exit velocity of the suspension at the Burner nozzle, an ever larger proportion of the carbon particles through the reaction chamber shot through and leaves this unchanged with the product gas.

The object was therefore a process for the production of synthetic gas to develop substances from aqueous suspensions of carbonaceous solids, whereby an almost complete implementation through an appropriate design of the burner of carbon is achieved.

It must be ensured that the as a suspension from the burner mouth exiting fuel jet is atomized in such a way that the heat supply into the fuel jet both from the outside, i.e. from the reactor wall, and from the inside, i.e. from the reaction zone takes place here.

To achieve this goal, the fuel jet must after leaving the nozzle can be converted into the shape of a hollow cone, which is as small as possible Distance from the inner wall of the reactor and without touching it, the reactor passes.

This problem is solved by a process for the production of synthesis gas by partial oxidation of, suspended in a liquid medium, containing carbon Particles with oxygen in a reaction zone at elevated pressure and temperature from 1000 to 16000C, with suspension and oxygen separated in the reaction zone to be introduced. It is characterized in that the material flows in the path a flow guide body is arranged symmetrically in the center.

The inventive method is used for the production of synthesis gas, in other words, a gas mixture composed primarily of carbon monoxide and hydrogen is.

As a carbon-containing raw material for gas generation you can get the most different types of hard coal, lignite but also solid residues as they are used in numerous chemical processes. Suitable are e.g. Carbohydrate residues. The pest substances are at an appropriate age brought and mixed with a suspending agent. Depending on the grain size and type of Solids, suspensions with a solids content of up to 75% by weight are obtained.

As a suspension medium, water is of the greatest importance.

But there can also be organic substances that are among the selected Conditions of suspension preparation are liquid, can be used. Which includes liquid fuels such as hydrogenation residues, heavy fuel oil and hydrocarbons.

For the oxidation, molecular oxygen is usually used in pure form Form or as a mixture with other gases, e.g. in the form of air.

The reaction is generally carried out at pressures of 10 to 120 bar and at temperatures from 1000 to 16000C, The feed materials, namely suspension the carbon-containing particles and oxygen are separated in the reactor fed. Of course, each of the two feedstocks can be used in several substreams are introduced into the reactor.

According to the method according to the invention, the material flows in the web In front of the reaction zone, a flow guide body is arranged centrally and symmetrically. The flow guide body has the shape of a truncated cone, a truncated paraboloid or a hyperboloid stump. It is expediently equipped with cooling and it The side of the flow guide body facing the reaction space has proven to be useful to be provided with a ceramic protective shield. This protective shield is used for prevention excessive heat radiation, maintaining a sufficiently high surface temperature, to prevent caking of coal or slag.

The task of the flow guide body is to control the gas flow and the suspension flow divert in the radial direction. On the flow guide body forms from an intimate Mixture of solid gate, liquid (i.e. water and / or liquid fuel) and Gas (oxygen or oxygen-containing gas, water vapor) forms a hollow cone. In this way it is ensured that the fuel particles enter the reaction space flow through axially. At the same time, the average residence time of each Particles in the reaction zone increased.

By dividing the flows of the feedstock into a hollow cone shape if the surfaces required for a quick reaction are created, when large amounts of suspension and oxygen are passed through. The one for evaporation the liquid phase of the suspension and for heating the carbon containing Particle required heat is applied to the Input materials from the outside through thermal radiation from the hot reactor wall and from the inside through radiation and convection of the reaction gas transferred. The partial oxidation of the fuel is therefore running no longer outside the fuel jet, but preferably inside the hollow cone from, so that the locally occurring high reaction temperatures here immediately act on the carbonaceous particles and accelerate their combustion.

The reactor wall experiences a change in the combustion process a considerably weakened thermal load compared to the previously outside the oxidation process taking place in the fuel jet. Therefore one reaches after The method according to the invention has a considerably longer service life for the brick lining than by the known method.

The shorter evaporation time of the liquid portion of the suspension, the reduced heating-up time for the fuel particles to react and the increased Residence times of the fuel particles in the reaction zone lead to an increase of carbon turnover.

There is a burner for carrying out the claimed method of separate, concentrically arranged lines for the suspension and for the inside oxygen, the reactor-side openings of which the nozzle of the burner form. It is characterized in that the nozzle is centrally symmetrical arranged, the shape of a truncated cone, a truncated paraboloid or hyperbo has a dull loid flow guide body.

In a common embodiment, suspension and oxygen are used fed to the reaction zone in two separate, concentrically arranged lines.

The flow guide body forms in the form of a truncated cone, of a paraboloid stump or hyperboloid stump widening the centric, symmetrically arranged inner shaft of the burner instead of the annular spaces that the form separate, concentrically arranged lines of oxygen and suspension, can also occur appropriately arranged bundles of lines or annular space segments.

The pipes are at the bottom of the burner the course of the Adjusted surface of the flow guide body. Appropriately, they are on Reinforced at the end to counteract possible abrasion. It is advisable, the reinforcement from one especially against abrasion and thermal loads resistant material like Ha8tello7 Stellite, Widia.

To the flow guide body the different conditions, such as they tend to occur in a continuous operation, adapt, this is with a mechanics located outside the friction system, which allow adjust the flow guide body in the direction of the central axis of the burner so that that the flow guide maintains its centrally symmetrical position.

This makes it possible to reduce the outlet gap of the oxygen supply and thus changing the exit velocity and exit angle of the oxygen, to adapt to changed operating conditions.

To protect against overheating, the flow guide body is equipped with a Cooling device provided, for example, using as evaporative cooling is made of water as a coolant.

The flow guide body is on the surface facing the reaction zone provided with a protective shield.

Because of the high thermal and chemical loads are on the material the protective shield made special demands. It consists of refractory materials and is attached to the surface by means of pins or retaining anchors. His task consists on the one hand in the heat radiation from the cooled flow guide body On the other hand, there should be a temperature on the surface of the protective shield prevail, which is high enough to cause harmful caking of coal or slag impede.

The one to be placed in the end point of the flow guide body on the reactor side Tangent should be the horizontal line in the plane of the face of the flow guide body is, cut at an angle of 5 to 45 °, preferably 10 to 20. For the The hollow cone shape of the oxygen flow results in an opening angle of 170 to 90 °, preferably 160 to 1300.

For optimal deflection, acceleration and atomization of the fuel jet reach, the outer wall of the oxygen line is 2 to 20 mm above the The outlet opening of the line concentrically surrounding it is preferred to the suspension. This measure ensures that the oxygen flow; deal with the Direction of suspension flow intersects at an angle of 450 to 90 ° 0 It it is advisable to choose a relatively low outflow speed of the suspension. Usually it is 3 to 12 m / sec.

In contrast, the rate of exhalation of oxygen should be relatively high lie. It must be at least 60 m / sec and can be up to that of the surrounding area The speed of sound assigned to the medium range, i.e. their values can range from 60 up to 330 m / sec.

An embodiment of the device according to the invention is shown in FIG 1 shown.

The device consists of an outer jacket 16, one concentric used, separating the product streams of coal-water suspension and oxygen Tube 13 and a centrally arranged inner shaft designed as a holding tube 10. The inner shaft 10 is at its end facing the reaction zone with a Flow guide body 14 provided, as a frustoconical, truncated paraboloid or hyperboloid frustum-shaped extension of the inner shaft is carried out, 8ein The front side is closed opposite the reaction zone and is provided by an additional Protective shield 8 made of ceramic protected against heat. The concentrically inserted pipe 13 is adapted to the course of the same at the level of the flow guide body 14, widens However, more than this to ensure that the oxygen flow meets and has the coal-water suspension at an angle of 450 to 900, to prevent rapid wear, reinforcements 17 via a line 1 the burner is the coal-water suspension in the annulus between Outer jacket 16 and inserted pipe 13 supplied. She leaves the burner through an annular gap opening 9. Oxygen or oxygen-containing gas is over a line 4 the annular space between the inserted tube 13 and the inner shaft 10 and leaves the burner through a Ringapalt opening 7.

To avoid overheating, the outer jacket 16 and the inner shaft 10 together with the flow guide body 14 provided with a cooling system. Through a line 2 cooling water is supplied via a line system 6 to the tip of the burner and leaves e.g. in the form of steam the burner via a line 3.

Several spacers 15 between the inner shaft 10 and tube 13 are attached, ensure the concentric, low-vibration guidance of the pipe 13th

On the outer jacket 16, a flange 5 is attached to the burner with the outer wall of a combustion chamber connects.

To better adapt the burner to different operating conditions or to adapt throughput rates, the flow guide body can be moved in the direction adjust the centric axis. The one arranged outside the pressurized system Adjustment mechanism 12 is used to avoid disruptive vibrations and for reasons precise setting implemented as a mechanical gear drive. The one for his activity required force can be applied in a known manner by electric motors and / or by means of Hydraulics are transferred. To a pressure-secured To enable implementation of the movable cold mount of the flow guide body, Resiliently deformable corrugated tubes 11 are used, which have an exit from below Prevent gases under pressure and at the same time act as compensators.

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Claims (11)

Claims 1. A process for bynthesegas production by partial Oxidation of carbon-containing particles suspended in a liquid medium with oxygen in a reaction zone at elevated pressure and a temperature of 1000 to 1600 ° C, with suspension and oxygen introduced separately into the reaction zone will. It is characterized in that there is a flow guide body in the path of the material flows is arranged centrically symmetrically. 2. The method according to claim 1, characterized in that the flow guide body is cooled. 3. The method according to claim 1 and 2, characterized in that the from the jacket surface or the tangent to the jacket surface of the flow guide body Angle formed with the horizontal is 5 to 45 ° C, preferably 10 to 25 ° C. 4. The method according to claim 1 to 3, characterized in that the Flow guide body on the side facing the reaction chamber with a ceramic Protective shield is provided. 5. The method according to claim 1 to 4, characterized in that the Outflow speed of the oxygen into the reaction space from 60 m / sec to 180 m / sec. 6. The method according to claim 1 to 5, characterized in that the Form an angle of 45 to 90 ° for the outflow direction of oxygen and suspension. 7. The method according to claim 1 to 6, characterized in that the The outflow speed of the suspension is 3 to 12 / sec. 8. Apparatus for performing the method according to claim 1 to 7 in the form of a burner, the suspension and oxygen in separate, each other concentrically surrounding supply lines the reactor-side openings, which the nozzle of the burner, feeds, characterized in that the nozzle has a centric arranged, the shape of a truncated cone, a paraboloid or hyperboloid truncated having flow guide body. 9. Apparatus according to claim 8, characterized in that the position of the flow guide body with the help of a mechanism in the direction of the central axis of the burner is adjustable 10. Apparatus according to claim 8 and 9, characterized in that, through the reactor-side end point of the flow guide body to be laid tangent with the horizontal an angle of 5 to 450, preferably Forms 10 to 250. 11. The device according to claim 8, characterized in that the line of oxygen corresponds to the shape of the flow guide body and by 2 to 20 mm is extended on the line of the suspension on the reactor side.